Which gene mutation is detected in 90-97% of patients with polycythemia vera and 50-60% of essential thrombocythemia patients?

Which gene mutation is detected in 90-97% of patients with polycythemia vera and 50-60% of essential thrombocythemia patients?

• A. BCR/ABL1 gene fusion
• B. JAK2 V617F
• C. PDGFRa mutation
• D. RUNX1 mutation

Answer: (B)

This question tests recognition of the mutation most strongly linked to polycythemia vera and essential thrombocythemia. The JAK2 V617F mutation is detected in about 90-97% of polycythemia vera patients and roughly 50-60% of essential thrombocythemia patients. This mutation causes constitutive activation of the JAK-STAT signaling pathway, driving increased production of blood cells—red cells in PV and platelets in ET—which explains the clinical features seen in these conditions. Because of its high prevalence and its role in the disease mechanism, testing for JAK2 V617F is a key diagnostic marker that helps distinguish these myeloproliferative neoplasms from reactive conditions and other disorders. The other mutations listed are associated with different diseases: BCR-ABL1 with chronic myeloid leukemia, PDGFRα mutations with other myeloid/neoplasm spectra (often with eosinophilia), and RUNX1 mutations with familial platelet disorders and leukemia risk. Thus, the JAK2 V617F mutation is the best answer.

This question tests recognition of the mutation most strongly linked to polycythemia vera and essential thrombocythemia. The JAK2 V617F mutation is detected in about 90-97% of polycythemia vera patients and roughly 50-60% of essential thrombocythemia patients. This mutation causes constitutive activation of the JAK-STAT signaling pathway, driving increased production of blood cells—red cells in PV and platelets in ET—which explains the clinical features seen in these conditions. Because of its high prevalence and its role in the disease mechanism, testing for JAK2 V617F is a key diagnostic marker that helps distinguish these myeloproliferative neoplasms from reactive conditions and other disorders. The other mutations listed are associated with different diseases: BCR-ABL1 with chronic myeloid leukemia, PDGFRα mutations with other myeloid/neoplasm spectra (often with eosinophilia), and RUNX1 mutations with familial platelet disorders and leukemia risk. Thus, the JAK2 V617F mutation is the best answer.